Adapting sheet metal for receiving a screw



Oct. 19, 1937. G; A. TINNERMAN 2,096,387

ADAPTING SHEET METAL FOR RECEIVING A SCREW Original Filed Dec. 30. 1956)5 X3 WIIIIIII/%IIIIIIIL INVENTOR. GEO/e65 4. 77V/VE/F/7/9/Y B flwk/ATTORNEYS.

Patented Oct. 19, 1937 PATENT OFFICE ADAPTING SHEET METAL FOR RECEIVINGCREW George A. Tinnerman, Rocky River, Ohio, assignor to Albert H.Tinnerman, Cleveland, Ohio Original application December 30, 1936,Serial No. 118,216. Divided and this application March- 26, 1937, SerialNo. 133,202

6 Claims.

This invention relates to threadless fasteners which are made of sheetmetal, and is a division of my copending application, Serial No. 118,216

filed Dec. 30, 1936.

An object of my invention is to make a-threadless fastener that can bemade from ordinary commercial quality cold rolled steel and thatpossesses the holding power of fasteners made from spring steel. Inaddition, the invention contemplates a shape of fastener, which enablesit to be formed out of sheet panels that comprise an integral part of anassembly, such as automobile bodies, gas or electric ranges, furnacejackets, metal furniture, metal partitions, refrigels, airplanecowlings, lamp bases, signs or many kindred types of assemblies whichemploy metal I ber.

sheet materials, as a part of their completed form. A further object ofthe invention is to make a fastener which may be constructedindependently I of the panel with which it is intended to be used sothat it can be suitable for holding assembly panels which are made ofsuch materials as fibre board and glass or vitreous coated metal sheets.Referring now to the drawing, Fig. 1 is a top plan view of a fastenerembodying my invention; Fig. 2 is a side view of a fastener shown inFig. 1; Fig. 3 is a longitudinal vertical section taken through thefastener of Fig. l and showing it in use with a threaded member; Fig. 4is a top plan view of a panel having fasteners embodying the presentinvention formed therein; Fig. 5 is a vertical section through a formingtool illustrating a step in the forming of the fastener; Fig. 6 is asection similar to that in Fig. 5 and showing another step in theformation of the fastener; Fig. '7 is a cross sectional view taken onthe line 'i1 in Fig. 2; Fig. 8 is a top plan view of. a fastener havinga modified form of a bolt opening therein, and Fig. 9 is a side view ofa fastener shown in Fig. 8. I

The fastener which I have illustrated, has been designed to havesufficient strength even though made out of cold rolled steel towithstand the endwise pull which is exerted during the tight eningoperation of the threaded holding mem- The fastener is adapted to bemade either in individual units or in the form of an impression on asheet panel. Thus, in Fig. l the individual fastener is shown as havingabody portion ID from which thread engaging portions H are deformed.These portions, in the form shown, include wall surfaces i2 which areinclined to the body portion and which terminate in substantially fiatportions l3 that are bent inwardly out of the plane of the inclined wallsurfaces l2 and are pitched to correspond to the helix of a threadedmember with which the fastener is intended to be used.

In the preferred arrangement, the portions l3 have a width that issubstantially equal to the depth of the thread on the bolt with whichthe fastener is intended to be used, as a result of which the forceexerted during the tightening operation does not impose an objectionablebending moment upon the thread engaging part of the fastener. Theportions l2 may be either substantially flat or slightly curvedtransversely, but in either case, the surface is such that itsintersection by any plane passing at a right angle through the bodyportion, and in a direction in which the tongues extend, would be astraight line.

In making the thread engaging portion, I prefer to utilize a tool whichwill slit the stock along parallel lines [5, and then draw out of itsplane that portion which lies between the slits IS. The slitting anddrawing operation may be performed by dies'20 and 21 respectively; thedie 21 having a cavity 22 into which the metal is adapted to be pressedby the die 20. This operation imparts toughness to the metal by coldworking it, the operation comprising a stretching as well as a formingoperation, as a result of which the area of the deformed metal is largerthan the area of the opening from which it has been drawn.

Fig. 5 shows the position of the dies during the drawing operation whileFig. 6 shows the position of them during the piercing operation. In Fig.6, the deformed metal fills the cavity in the lower die while thepunch23 which is positioned centrally within the die 20 extends throughthe metal, thereby shearing oil a part of it, so as to form theaperture, through which a threaded fastening member 25 may extend.

The die 20 may have a yieldable connection, by means of a spring 26,with a plunger 21, that is adapted to be reciprocated in any well knownmanner. The spring 26 is sufficiently strong that the metal is drawnfrom the body portion of the fastener and forced against the wall of thecavity 22 before the punch 23 pierces the metal to form the threadreceiving aperture. A convenient way of supporting the punch 23 withinthe carrier or plunger 21, is to provide a shoulder which abuts thecarrier against the Wall 4|, which forms the seat for the spring 26. Thedie construction shown may be satisfactorily used either for formingindividual fasteners or for making the fastener impressions in the bodyof a sheet was deformed. This may be accomplished either by pressing themetal with suflicient force to make it flow laterally, or by bowinginwardly the longitudinal connecting strips 9 on the body of thefastener. In either case, the connecting strips 9 provide an abutment asshown by the broken lines I I a in Fig. 7 against which the laterallyprojecting ends of the tongues may engage in case they are drawn to anexcessive degree during the bolt-tightening operation. In this way, thetongues are prevented from being pulled through the fastener at anytime.

In Figs. 8 and 9, I have shown a modification of my invention whereinthe bolt engaging portion comprises a strip 30 that is drawn from thebase in'the same manner as heretofore described in connection with thefastener of Fig. 1, but wherein the bolt receiving opening is formed bysevering the strip only at one edge as at 3 I. Such severing operationforms the tongues 32 and 33 which may be bent in opposite directions soas to make the marginal edge of the bolt receiving opening in the formof a helix that corresponds to that on the thread with which thefastener is intended to be used.

A fastener made in accordance with the present invention has sufllcientstrength to resist the tendency of the threaded member to pull through,wherefore it can be made of cold rolled stock and used satisfactorilywith a threaded holding member that is commercially known as awoodscrew. The cold working of the metal, resulting from the forming andstretching operation, imparts a degree of hardness to the threadengaging portions of the fastener which makes it suitable for use inimpressions that are provided in multiple from an unhardened sheet metalpanel. Thus,'I have greatly extended the usefulness of threadlessfasteners in automotive and cabinet assembly. A further advantage of myinvention is the fact that the forming tools may be satisfactorily usedeither for making individual fasteners or for making individualimpressions in a sheet metal panel upon a single stroke of thereciprocating die.

I claim:-

1. The method of adapting unhardenedsheet metal for the reception of ascrew or the like, which comprises, slitting, drawing and stretching anarea of the sheet out of its plane, thereby providing a substantial wallprojecting out of said plane of greater area than the space from whichit is drawn, and providing in the wall thus ob- 1tlalined an opening toreceive the screw or' the 2. The method of adapting unhardened sheetmetal for the reception of a screw or the like, which comprises,slitting, drawing and stretching an area of the sheet out of its plane,thereby providing a substantial wall projecting out of said plane ofgreater area than the space from which it is drawn, providing in thewall thus obtained an opening to receive the screw and distorting aportion of said wall adjacent the opening thereby providing a threadengaging portion which lies on a helix corresponding to the threads ofthe screw to obtain uniform threaded engagement therewith.

3. The method of adapting unhardened sheet metal for the reception of ascrew or the like, which comprises, drawing an area of the sheet out ofits plane to provide a substantial wall projecting out of said plane ofgreater area than the space from which it is drawn, stretching the wallthereby providing a wall portion which is hardened and substantiallyflat, and providing in the said hardened wall portion an opening therebypresenting a hardened thread engaging out of its plane to provide asubstantial wall pro- I jecting out of said plane ofgreater area thanthe space-from which it is drawn, stretching the" wall thereby providingawall portion which is hardened, and providing an openingin the saidhardened wall portion thereby 4 presenting a hardened thread engagingportion adapted to engage the screw on a planesubstantially at rightangles to the axis thereof'jwhereby said projecting wall bolsters thesaid hardened thread engaging portion and prevents ,the same from beingpulled through the sheet ;when the screw.

is drawn up, and distorting'said'thread engaging portion to lie on ahelix corresponding tothat of the threads of the screwto obtain mosteffective, uniform threaded engagement therewith.

5. The method of adapting unhardened sheet metal for the reception of-ascrew or the like, which comprises, slitting-and drawing an area ofthe'sheet out of its plane, thereby providing a substantial wall"projecting out .of-'said plane of greater area tha'ngthe spaceir'omwhich it is drawn, and cold working said wall thereby pro viding astretchedwall portion having an element projecting laterally beyond theoutline of the space from which the wall is drawn, and pro-' viding inthe said wall an opening to receive the screw. t y I I 6. The method(if-adapting unhardened sheet metal for the receptioh-= of "escrowor'the like,

- which comprises, slitting, drawing and, stretching of an area of thesheet out ofitsplane to. provide a substantial wall projectingout ofsaid I plane of greater area than the spacelfrom which it is drawn andproviding in the projecting wall thusobtained an, opening therebypresenting means for receiving the screw comprising av pair ofindependently movable projecting wall members adapted to' coact inengaging the screw or the like.

GEORGE A. TINNERMAN, I

